The present invention relates to a sheet feeding apparatus and an image forming apparatus, and particularly relates to a sheet feeding apparatus detachably mounted to an image forming apparatus for feeding sheets one at a time, and an image forming apparatus equipped with the same.
Conventionally, in order for an image forming apparatus to file sheets with images formed thereupon, a punching process is performed on the sheets in a discharge apparatus disposed in the image forming apparatus or at downstream of the image forming apparatus. For example, Japanese Utility Model Publication (Jikkai) No. 62-92261 has disclosed technology relating to a hammer for striking a scrap receptacle device to flatten punch hole scraps inside the scrap receptacle device. Japanese Patent Publication (Tokkai) No. 04-179588 has disclosed technology relating to an automatic hole punching apparatus that is arranged near a discharge apparatus (a sorter). Japanese Patent Publication (Tokkai) No. 11-311883 has disclosed technology relating to an arrangement of a hole punching apparatus adjacent to a photoconductor drum inside of an image forming apparatus.
However, in the conventional technologies described above, the following problems are noted. a) A sheet is transferred for a considerable long distance from a sheet feeding position to a position where a hole is punched. Thus, it is easy for the sheet to be excessively skewed, thereby causing a problem of correcting the skew of the sheet. As a result, the hole tends to be punched in a wrong position in the sheet. b) In a case that the hole punching process is performed at a position in an image forming apparatus where many members are concentrated, it is difficult to remove a sheet when a paper jam occurs. Also, a scrap receptacle device needs to be disposed at a position in an image forming apparatus where many members are concentrated. Thus, it is difficult to remove punch scraps. c) A paper jam occurs more easily when punching holes than when a sheet is transferred normally. In a case that a hole punching unit where a paper jam easily occurs is arranged inside an image forming apparatus or a discharge apparatus far away from a sheet feed position, a subsequent sheet is supplied when a paper jam occurs due to the hole punching process, thereby wasting the subsequent sheet. d) In a case that the scrap receptacle device is disposed inside the image forming apparatus or below a sheet feed path in the discharge apparatus, it is necessary to extend the scrap receptacle device in the horizontal direction to ensure enough capacity to receive hole punch scraps. Therefore, the hole punch scraps are accumulated directly under hole punching members (such as a circular blade for punching holes). As a result, only a smaller amount of the punch scraps can be retained relative to an actual capacity of the scrap receptacle device, thereby decreasing space efficiency. In order to improve the space efficiency, it has been conceived to disperse the hole punch scraps to an area away from the hole punching device. However, it is required to provide a separate mechanism for shaking the hole punching device to disperse the hole punch scraps.
In view of the aforementioned problems, an object of the present invention is to provide a sheet feed apparatus and image forming apparatus in which holes are securely punched in the sheets without wasting the sheet when the paper jam occurs.
In order to attain the aforementioned objectives, according to the first aspect of the present invention, a sheet feeding apparatus detachably mounted to an image forming apparatus for feeding sheets one at a time includes storage means for stacking and storing the sheets, sheet feeding means for feeding the sheets stacked and stored in the storage means one at a time, register means for abutting against a leading edge of the sheet fed by the sheet feeding means in a feeding direction and for allowing the sheet to move further downstream after removing skew of the sheet by curling the sheet, and hole punching means for punching holes in the sheets whose skew is removed by the register means.
According to this aspect of the present invention, the sheets are stacked and stored in the storage means, and the sheet feeding means feeds the sheets stacked and stored in the storage means one at a time. The register means abuts against the leading edge of the sheet fed by the sheet feeding means in the sheet feeding direction for curling the sheet to remove the skew thereof, and then allows the sheet to travel further downstream. Then, the hole punching means punches the holes in the sheets whose skew is removed by the register means. According to this aspect, because the sheet feeding apparatus itself is provided with the hole punching means, the sheet is transferred for a short distance, thereby making it difficult for the skew (shift) to happen when the sheet is transferred. Therefore, it is easier for the register means to correct the skew of the sheet, and it is possible for the hole punching means to punch the hole in the sheet more accurately. The hole punching means where a paper jam easily occurs is disposed in the sheet feeding apparatus, and the sheets are fed one at a time from the sheet feeding means. Therefore, a subsequent sheet is not fed when the paper jam occurs, thereby eliminating sheet waste. In this case, in addition to the hole punching members for punching the hole in the sheet, if the hole punching means includes scrap receptacle means for receiving hole punch scraps from the sheets with holes punched by the hole punching member, the sheet feeding apparatus itself can receive the hole punch scraps with the scrap receptacle means, thereby making it easy to discard the scraps.
In order to solve the aforementioned issues, according to the second aspect of the present invention, a sheet feeding apparatus detachably mounted to an image forming apparatus for feeding sheets one at a time includes storage means for stacking and storing the sheets; sheet feeding means for feeding the sheets stacked and stored in the storage means one at a time; register means for abutting against a leading edge of the sheet fed by the sheet feeding means in a sheet feeding direction and for allowing the sheet to move further downstream after removing skew of the sheet by curling the sheet; a sheet feed path for guiding the sheet fed by the sheet feeding means in a vertical direction; hole punching means for punching holes in the sheets guided in the sheet feed path; and scrap receptacle means disposed along the sheet feed path for receiving hole punch scraps from the sheet with holes punched by the hole punching means. According to this aspect, the scrap receptacle means is disposed along the sheet feed path arranged substantially vertically to receive the hole punch scraps. Thus, in addition to the effects attained through the first aspect, it is possible to provide a space for disposing the scrap receptacle means easily. Furthermore, the scrap receptacle means is disposed extending substantially in the vertical direction. Thus, the hole punch scraps are dispersed while falling to fill the scrap receptacle means from the bottom, thereby making it possible to omit a structure for dispersing the hole punch scraps inside the scrap receptacle means as shown in the conventional apparatus.
According to the third aspect of the present invention, a sheet feeding apparatus detachably mounted to an image forming apparatus has a plurality of sheet feeding units that can be stacked in a vertical direction. The sheet feeding units include storage means for stacking and storing sheets; sheet feeding means for feeding the sheets stacked and stored in the storage means one at a time; and sheet feeding path for guiding the sheet fed by the sheet feeding means to the image forming apparatus. The sheet feeding apparatus feeds the sheets to the image forming apparatus one at a time. At least one of the sheet feeding units located at the farthermost downstream in the sheet feeding direction is provided with hole punching means for punching a hole in the sheet guided to the sheet feeding path. According to this aspect, among the stacked sheet feeding units, at least one of the sheet feeding units located at the farthermost downstream in the sheet feeding direction is provided with hole punching means. Accordingly, the feeding unit can perform the hole punching process on the sheet fed from any other sheet feeding units, thereby making the sheet feeding apparatus compact and simple. In this case, similar to the first and the second aspects of the invention, it is preferable that at least the sheet feeding unit located at the farthermost downstream is provided with register means for abutting against a leading edge of the sheet fed by the sheet feeding means in the sheet feeding direction and for allowing the sheet to move toward downstream after removing skew of the sheet by curling the sheet. It is also preferable to form the sheet feeding path in a substantially vertical direction, and to provide scrap receptacle means extending along the sheet feeding path for receiving hole punch scraps from the sheet punched by the hole punching means.
Also, in the second and third aspects, the scrap receptacle means may be arranged on a side opposite to the sheet feeding means with the sheet feeding path in between. Thus, it is possible to dispose the scrap receptacle means extending along the sheet feeding path without any restriction in a space caused by the sheet feeding means. In this case, opening and closing means may be further provided at a side opposite to the sheet feeding means with the sheet feeding path in between so that an operator can access to the scrap receptacle means. Further, in the first to third aspects, support means may be provided, so that the support means can support the storage means and hole punching means to be movable between a sheet feeding position where the sheet feeding means feeds the sheets one at a time and a refilling position where the sheets are refilled in the sheet feeding means. Thus, the storage means and hole punching means can be moved to the refilling position with the support means, thereby making it possible to handle a paper jam easily. Also, in a case that the scrap receptacle member and the scrap receptacle means are moved together to the refilling position, it is possible to discard the scraps easily from the scrap receptacle member or the scrap receptacle means. Further, in a case that hand-feed means is disposed at upstream of the hole punching means for manually feeding the sheets, it is possible that the hole punching means punches holes in the sheet fed manually as well as the sheet fed from the sheet feeding means.
According to the fourth aspect of the present invention, an image forming apparatus is provided with the sheet feeding apparatus according to the first to the third aspects. An image forming apparatus may be provided with the sheet feeding apparatus described above.